Electrical issue (and some smoked wires)

[Eomund]

So Had my brake lights go out on my way home. Fun times, I started poking around and was able to find a blown fuse. While working on figuring out where the short was I smoked some wires.

 

the fuse in the yellow box is the one that was popping. This isn't my box, mine is sadly in much worse shape.

 

If this image is to be believed, this fuse is only for the horn and brake lights.

 

First, can someone confirm that that's all this fuse is for?

 

I'm going to tear into it tomorrow and replace the fucked up wires. I just want to make sure I know that this is the only set of wires that can be causing this.

 

any input is appreciated. Thanks!

[wayno]

That 1969 fuse block is a different fuse block than your 1972 fuse block, they may be wired differently.

[Eomund]

32 minutes ago, wayno said:

That 1969 fuse block is a different fuse block than your 1972 fuse block, they may be wired differently.

I found a wiring diagram here. 

https://ratsun.net/topic/45389-521-color-eletrical-wiring-diagram/

And it seems to confirm this. And the wiring path thank God seems to be simple 

[Eomund]

Update. Figured out the issue and replaced the smoked wire. Turns out my button completely fucked up and turned into a dead ground. It's fried. I have a new one coming tomorrow. 

 

One more glitch which I'll fix once I get a second body. Removing the button caused a l wheel cylinder that's going out to suck up air. So now my brakes need to be bled. I knew it had a weep and I was gonna fix that next check. But I didn't know it could do that. 

 

Shell be back on the road tomorrow

[yenpit]

On 3/13/2020 at 9:45 AM, Eomund said:

Update. Figured out the issue and replaced the smoked wire. Turns out my button completely fucked up and turned into a dead ground. It's fried. I have a new one coming tomorrow. 

 

One more glitch which I'll fix once I get a second body. Removing the button caused a l wheel cylinder that's going out to suck up air. So now my brakes need to be bled. I knew it had a weep and I was gonna fix that next check. But I didn't know it could do that. 

 

Shell be back on the road tomorrow

 

Button??  Are you referring to the brake light switch at the pedal?  I ALWAYS replace them on every Datsun project, cuz even the OEM switch is kinda crappy quality & of course they do wear out!  They ARE still available from Nissan. 

 

I have a 1972 521, original fuse box was toast, bought an NOS Niles fuse box on eBay from Thailand, was NOT correct, but I was able to easily modify it to match my original fuse box.  Haven't installed it yet 🙄 .  I also bought the Blue Sea aftermarket fuse box, but won't swap over to that right now. 

 

Be careful with the 521 wiring diagrams found online.........I'm not sure they are correct for the USA spec 521's.  They show the headlight switch as a 6 wire, but my 72 521 is a 4 wire.  The JDM spec headlight switch was a 6 wire, cuz they had factory fog lamps that were switched by the headlight switch!